1. Field of the Invention
The invention relates generally to the treatment of urogenital conditions. More particularly, the invention relates to devices and surgical techniques for use in treating female pelvic organ prolapse.
2. Description of the Related Art
When intra-abdominal pressure pushes the vagina outside the body, vaginal prolapse can develop. In normal circumstances, the levator ani muscles close the pelvic floor, supporting it from below while fascia a ligaments support. Increases in abdominal pressure, failure of the muscles to keep the pelvic floor supported, and damage to the ligaments and fascia all contribute to the development of prolapse. In addition, if a woman has a hysterectomy, the vaginal angle may be altered and ligament support reduced, causing increased pressure at a more acute angle, accelerating the prolapse.
The vagina and uterus are generally composed of two different types of tissue. First, there are fibrous connective tissues that attach these organs to the pelvic walls (cardinal and uterosacral ligaments; pubocervical and rectovaginal fascia). Second, the levator ani muscles close the pelvic floor so the organs can rest on the muscular shelf. It is when damage to the muscles open the pelvic floor or during the trauma of childbirth that the fascia and ligaments are strained. Breaks in the fascia allow the wall of the vagina or cervix to prolapse downward.
A variety of factors can cause genital prolapse in women. It is thought that individual women have differing inherent strength of the relevant connective tissue. The loss of connective tissue strength may be associated with damage at childbirth, deterioration with age, poor collagen repair mechanisms, and poor nutrition. Loss of muscle strength might also be associated with neuromuscular damage during childbirth, neural damage from chronic straining, and metabolic diseases that affect muscle function. Other factors involved in prolapse include increased loads on the supportive system, as seen in prolonged lifting or chronic coughing from chronic pulmonary disease, or some disturbance in the balance of the structural support of the genital organs. Possible factors may also include obesity, constipation, and a history of hysterectomy.
Anterior vaginal wall prolapse causes the vaginal wall to fail to hold the bladder in place. This condition, in which the bladder sags or drops into the vagina, is termed a cystocele. There are two types of cystocele caused by anterior vaginal wall prolapse. Paravaginal defect is caused by weakness in the lateral supports, mainly the attachment of the bladder to the endopelvic fascia; central defect is caused by weakness in the central supports, mainly the fascial layers. A transverse defect, causing cystecele across the vagina, may also occur.
Posterior vaginal wall prolapse results in descent of the rectum into the vagina, often termed a rectocele, or the presence of small intestine in a hernia sac between the rectum and vagina, called an enterocele. There are generally four types of enteroceles based on suspected etiology. Congenital enteroceles are thought to occur because of failure of fusion or reopening of the fused peritoneal leaves down to the perineal body. Posthysterectomy vault prolapses may be “pulsion” types that are caused by pushing with increased intra-abdominal pressure. They may occur because of failure to reapproximate the superior aspects of the cardinal and uterosacral ligaments, pubocervical fascia and the rectovaginal fascia at the time of surgery. Enteroceles that are associated with cystocele and rectocele may be from “traction” or pulling down of the vaginal vault by the prolapsing organs. Finally, iatrogenic prolapses may occur after a surgical procedure that changes the vaginal axis, such as certain surgical procedures for treatment of incontinence. With regard to rectoceles, low rectoceles may result from disruption of connective tissue supports in the distal posterior vaginal wall, perineal membrane, and perineal body. Mid-vaginal and high rectoceles may result from loss of lateral supports or defects in the rectovaginal septum. High rectoceles may result from loss of apical vaginal supports. Posterior or posthysterectomy enteroceles may accompany rectoceles.
Vaginal prolapse and the concomitant anterior cystocele can lead to discomfort, urinary incontinence, and incomplete emptying of the bladder. Posterior vaginal prolapse may additionally cause defecatory problems, such as tenesmus and constipation.
Various techniques have been tried to correct or ameliorate the prolapse and its symptoms, with varying degrees of success. Nonsurgical treatment of prolapse involves measures to improve the factors associated with prolapse, including treating chronic cough, obesity, and constipation. Other nonsurgical treatments may include pelvic muscles exercises or supplementation with estrogen. These therapies may alleviate symptoms and prevent worsening, but the actual hernia will remain. Vaginal pessaries are the primary type of nonsurgical treatment. However there can be complications due to vaginal wall ulceration.
A variety of surgical techniques are used for the treatment of anterior vaginal prolapses. In the small proportion of cases in which the prolapse is caused by a central defect, anterior colporrapphy is an option. This surgery involves a transvaginal approach in which sutures are used to reapproximate the attenuated tissue across the midline of the vagina. More commonly, the prolapse is due to a lateral defect or a combination of lateral and central defects. In these instances, several surgical techniques have been used, such as a combination of an anterior colporrapphy and a site-specific paravaginal repair. Both abdominal and vaginal approaches are utilized. Biological or synthetic grafts have been incorporated to augment repair.
Similarly, the treatment of posterior vaginal prolapses may vary. If symptoms are minimal, nonoperative therapy such as changes in activities, treatment of constipation, and Kegel exercises might be appropriate. Again, both vaginal and abdominal approaches are used, involving sutures to reapproximate the attenuated tissue and possibly a biological or synthetic graft to augment the repair.
The vaginal vault may be attached to the sacrum by use of mesh or fascia in a procedure known as Sacral colpopexy. The surgery may be performed through an abdominal incision or laparoscopically, however certain undesirable complications may occur. If synthetic mesh is used, it is typically carefully customized or assembled into a special shape by the surgeon. Sacral colpopexy can also be a tedious, challenging surgical procedure, with an average procedure length of 247 minutes reported in Winters et al., Abdominal Sacral Colpopexy and Abdominal Enterocele Repair in the Management of Vaginal Vault Prolapse, Urology 56 (Suppl 6A) (2000): 55-63. Some of this time is attributed to the time required for the surgeon to fashion the implant. In addition, it is often required to correct multiple pelvic floor abnormalities simultaneously, which further increases the duration of the surgery.
Another procedure, called sacrospinous fixation, is also used to treat vaginal vault prolapse. This procedure involves attaching the vaginal vault to the sacrospinous ligament, which requires specialized skills and has the disadvantage of tending to place the vagina in an artificial anatomical position.
It is also possible to use various sling procedures to treat prolapse conditions. A sling procedure is a surgical method involving the placement of a sling to stabilize or support the bladder neck or urethra. There are a variety of different sling procedures. Slings used for pubovaginal procedures differ in the type of material and anchoring methods. In some cases, the sling is placed under the bladder neck and secured via suspension sutures to a point of attachment (e.g. bone) through an abdominal and/or vaginal incision. Examples of sling procedures are disclosed in U.S. Pat. Nos. 5,112,344; 5,611,515; 5,842,478; 5,860,425; 5,899,909; 6,039,686; 6,042,534; and 6,110,101.
Although serious complications associated with sling procedures are infrequent, they do occur. Complications include urethral obstruction, development of de novo urge incontinence, hemorrhage, prolonged urinary retention, infection, and damage to surrounding tissue and sling erosion.
The TVT Tension-free Vaginal Tape procedure utilizes a Prolene™ nonabsorbable, polypropylene mesh to treat incontinence. A plastic sheath surrounds the mesh and is used to insert the mesh into the patient. Abdominal and vaginal incisions are made, followed by implantation of the mesh using two curved, needle-like elements to push the mesh through the vaginal incision and into the paraurethral space. Using the procedure described elsewhere, the mesh is looped beneath the bladder neck or urethra. The sling is positioned to provide appropriate support to the bladder neck or urethra. When the TVT mesh is properly positioned, the cross section of the mesh should be substantially flat. In this condition, the edges of the mesh do not significantly damage tissue. Shortcomings and attempts to address these shortcomings and other problems associated with certain tape procedures are disclosed in PCT publication nos. PCT WO 00/74613 and PCT WO 00/74594.
Due to the tough fibrous nature of fascia and muscle tissues, forceps or similar instruments are needed to withdraw the needles through the abdominal wall. However, the smooth surface of the needles, which facilitates insertion through the tissues, prevents secure attachment of the forceps onto the needles, causing slippage or detachment of the forceps during the withdrawal procedure. Improper placement of certain meshs is also particularly troublesome. If the mesh is too loosely associated with its intended physiological environment, the mesh may be ineffective in supporting the urethra and treating incontinence. Surgeons may exacerbate certain problems by improperly attempting to adjust the tension of a sling. If insufficient adjustment force is applied, the sling will simply exhibit a memory property and return to its original, unacceptable position. As a result, surgeons are tempted to use a great deal of force in order to loosen a sling that is perceived to be too tightly associated with its intended physiological environment. If excessive force is applied, the mesh will plastically deform and the cross section of the mesh will become arcuate. Excessive deformation may also result in a lack of efficacy.
U.S. Pat. No. 6,695,855 (Gatson) describes a device for treating a prolapse by vaginal suspension. The device includes an elongated, flexible pierced material, a suture connected to the material, and a suture needle joined to the suture. The device is long enough to enable posterior suspension of the vagina at the front part of the sacrum. The other end of the device includes a distal portion having a width such that it can cover at least a large part of the posterior part of the vagina, a rounded cut-out with dimensions that enable it to be engaged around the base of the vagina on at least a large part of the lower half of the wall of the vagina. The suture is connected to the article so that it is offset sidewise in relation to the cut-out.
PCT Publication No. WO 00/27304 (Ory) discloses a suspension device for treating prolapse and urinary incontinence. The device comprises at least one filiform suspension cord with limited elasticity and at least two anchoring parts linked to the ends of the cord.
U.S. Pat. No. 5,112,344 and PCT Publication No. PCT/US02/32284 disclose surgical devices for female pelvic health procedures. The IVS TUNNELLER™ device (available from U.S. Surgical, Norwalk, Conn.) comprises a fixed delta wing handle, a hollow metal tube, and a stylet that is placeable within the tube. The stylet has a rounded plastic tip on one end and an eyelet on the other end. The device may be used to implant a polypropylene tape for infracoccygeal sacropexy and other surgical procedures. A single rigid, hollow, metal tube is associated with the IVS TUNNELLER™ device. This tube passes through two separate regions of the patient's body with the attendant risk of cross-contamination. The outer diameter is also relatively large (about 0.25 inch) with the attendant risk of tissue damage due to such large diameter. The polypropylene tape supplied with the IVS TUNNELLER™ is of a thin, rectangular shape and is not believed to be optimally sized and shaped to afford concomitant procedures such as enterocele, cystocele, and/or rectocele repairs.
There is a need for a minimally invasive yet highly effective device and method that can be used to treat pelvic organ prolapse with minimal or no side effects. Such a device should reduce the complexity of procedures that are currently available while being biocompatible, adjustable, and non-toxic. Treatment methods using the device should reduce pain, operative risks, infections and post operative hospital stays, and generally improve a patient's quality of life.